Various semiconductor light emitting elements that emit not only in the visible light band of red, green, blue, etc., but also in the wide wavelength band from infrared light to ultraviolet light are being utilized as small and low power-consumption light emitting elements. Optical semiconductor devices also have been developed to emit white light by a combination of a fluorescer and a semiconductor light emitting element such as, for example, a blue LED (Light Emitting Diode).
The most versatile optical semiconductor device currently used as a product is a semiconductor light emitting element in which a semiconductor layer is epitaxially grown on a substrate. In other words, the individual semiconductor light emitting elements are obtained by epitaxially growing the semiconductor layer on a substrate such as GaAs, GaP, sapphire, etc., forming electrodes and the like, and subsequently subdividing. Then, the optical semiconductor devices are completed by mounting the semiconductor light emitting elements thus obtained onto leadframes, SMD (Surface Mounting Device)-type housings, various mounting substrates, etc., performing the prescribed interconnects, and sealing the semiconductor light emitting elements with a transparent resin.